1. Field of the Invention
The present invention relates to an image display apparatus and an image display method using a self-luminous display panel such as an organic EL (Electro-Luminescence) panel, and more particularly, to a technique for correcting deterioration in light-emission luminance.
2. Description of the Related Art
There have been developed various kinds of display apparatuses displaying an image through self emission of pixels arranged in a matrix form on a display panel. For example, display apparatuses using an organic EL panel have been put into practical use. The organic EL panel is an image display device that has high light-emission luminance of pixels and is excellent in displaying high-luminance images with high precision.
In a standard image signal such as a television broadcast image or a movie image, there are various standards for an aspect ratio which is a ratio between the horizontal length and the vertical length of an image. Therefore, measurements have to be taken in order to display an image with a display apparatus having an aspect ratio different from that of an image signal.
For example, when an image is displayed using an input image signal with a display apparatus having an aspect ratio different from the original aspect ratio of the image signal without changing the aspect ratio of the image, black areas, that is, non-display areas are provided in upper and lower sides or right and left sides of the image to deal with a difference.
FIGS. 12A to 12C are diagrams illustrating examples in which aspect ratios of images are different.
An example of a display raster size of 16:9 is shown in FIG. 12A. An example of a display raster size of 4:3 is shown in FIG. 12B. An example of a display raster size of a cinema scope size (2.35:1) is shown in FIG. 12C.
When the display panel has a size with an aspect ratio of 16:9, an image in FIG. 12A is displayed on the entire panel. When an image with an aspect ratio of 4:3 in FIG. 12B is displayed, non-display portions occur in the right and left sides of the screen. When an image with a cinema scope size in FIG. 12C is displayed, non-display portions occur in the upper and lower sides of the screen.
In FIGS. 12A to 12C, three representative raster sizes are shown. In effect, there are a large number of raster sizes.
When the raster size of an image to be displayed is different, positions of the non-display portions on a screen are different.
Japanese Unexamined Patent Application Publication No. 2007-240798 discloses a technique for detecting and correcting deterioration in light-emission luminance of pixels of a display panel of a display apparatus. In Japanese Unexamined Patent Application Publication No. 2007-240798, dummy pixels are provided in the process of detecting the deterioration to measure an average light-emission luminance of the dummy pixels.